"A lot of our people didn't like parts of what was agreed," he told an event in east Belfast – and decided they wanted the DUP "instead of us" at the heart of government.

But he asked if anyone felt they had profited from a better deal as a result of switching to the DUP.

Mr Nesbitt said there had been a "significant failure to deliver" on the promise of the Good Friday Agreement.

But he did not repeat his recent line that the party should be prepared to apologise for the 1998 accord which marked its 15th birthday yesterday.

Instead, Mr Nesbitt said: "This is not where Northern Ireland was supposed to be in 2013. Maybe it's time to stop talking about what we have achieved and focus instead on what we have failed to achieve."

His remarks came at a party gathering at which a five-point 'commitment card' was also launched. It's five points are: